Automatic fuel-feed system for carbureters



C. C. BRADBURY. J AUTOMATIC FUEL FEED SYSTEM FOR CARBURETERS APPLICATION FILED APR.12. ms.

1 ,364:,479. Patented Jan. 4, 1921.

UNITED STATES PATENT OFFICE.

CLIFFORD C. BRADBURY, OF CHICAGO, ILLINOIS, ASSIGNOR TO ARTHUR L. PAYTO'N,

OF CHICAGO, ILLINOIS.

AUTOMATIC FUEL-FEED SYSTEM FOR CARBURE'IERS.

Specification of Letters Patent. Patented J an. 4, 1921'.

Application filed April 12, 1916. Serial No. 90,634.

T 0 all whom it may concern Be it known that I, CLIFFORD C. BRAD- BURY, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Automatic F uel-Feed Systems for Carbureters, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to automatic fuel feed systems for carbureters. The invention has for its object mechanism by which the fuel may be lifted from a main supply tank at a lower level than the carbureter to a secondary supply tank at or above the level of the carbureter, such, for example, as the float chamber of the carbureter itself, the depression in pressure produced by the suction of the engine being used to cause the flow of gasolene from the lower to. the higher level.

The commercial carburetors for automobiles as constructedat the present time are so designed and proportioned that at the lowest engine speeds, that is, at what is known asidling speed, a diiferencein pressure between the end of the spraynozzle inside the atomizing chamber and the surface of the gasolene in the float chamber of the equivalent to 1% to 2 inches of gasolene is maintained. This difference in pressure is ordinarily brought about by restricting the atmospheric entrance into the atomizing chamber of the carbureter. It is the object of my invention to so arrange my carbureter that the same difference in pressure between ,the atomizing chamber and the surface of the gasolene in the float chamber may be maintained as is maintained with the ordinary gravity feed carbureter, but at the same time to bring about a general depression in pressure both inside of the atomizlng v chamber and within the float chamber, so that the general depression may be used for lifting the gasolene from the main supply tank to the carbureter. In order, furthermore, that this general depression may be very slight but may still be sufiicient to lift gasolene through a distance which may under some circumstances amount to 30 or lene, so that the specific gravity of the gasolene is automatically reduced and automatically proportioned to the available suction. This can only be accomplished where the tube leading from the main gasolene suppflly to'the secondary gasolene supply is su ciently small in diameterthat the capillary attraction or surface tension-of the gasolene will cause the bubbles of air to extend entirely across the tube and thus at least for a short period of time serve as effectual dams to prevent the gasolene which is entrapped between the bubbles of air from returning past the air to the main supply tank..

This automatic arrangement is such that even though 'the'suction is suflicient only for lifting gasolene a distance of two or three inches when the gasolene is not intermingled with air, it will nevertheless be liftedany distance, even 40 or 50 inches, in suflicient quantities to supply all the needs of the ordinary carbureter when it is mixed with air by the automatic mixing arrangement of my invention.

One specific structure, by means of which these results are brought about, is fully described in the following detailed description and is illustrated in the accompanying drawings, in which Figure 1 illustrates a side elevational view of an automobile provided with the system of my invention, some of the parts of the automobile being broken away to more clearly illustrate the construction of the several parts of the system.

Fig. 2 is an enlarged detailed view of the air intake openings in the fuel conduit and the means for regulating the air to the openings from the outside of the reservoir.

Fig. 3 is a vertical cross sectional view of the carbureter illustrated in Fig. 1. This view is taken along the line 33 of Fig. 1, looking in the direction indicated by the arrows.

Similar characters of reference refer to similar-parts throughout the several views.

The system of my invention is intended primarily to be used on automobiles and is thus illustrated in Fig. 1, wherein 4 illustrates the internal combustion engine provided with the intake manifold 5. The carbureter 6 is arranged to communicate with the intake manifold in the usual manner and may receive air through a conduit 7, terminating at a heater for heating the in- The carbureter is also provided with the auxiliary air intake mechanism indicated generally at 8 and the usual float chamber 9 communicating with the fuel supply conduit 10. The fuel chamber may, if desired, be

provided with the float 11 to discontinue communication between the fuel chamber and the supply conduit when the fuel reaches a certain level within the chamber. Located below the level of the fuel chamber of the carbureter is a supply reservoir 12 containing a vent opening 13. The conduit 10 extends downwardly from the carbureter through the top of the supply reservoir 12 and into the fuel contained therein. That portion of the conduit 10 which'is disposed within the fuel reservoir is provided with a plurality of restricted air intake openings i k-14 which are spaced one above the other throughout such portion of the conduit. The upper one of the apertures 14 is positioned to at all times lie above the level of the fuel contained in the reservoir. Carried by the conduit 10 and extending around the apertures 14: is an outer tube 15 open at the bottom to admit the fuel around the conduit 10, as illustrated in Fig. 2. The upper end of the outer tube'15 is provided with a single air intake opening 16 which is regulated by means of a screw 17 extending through the top of the reservoir. The holes 1414: in that portion of the conduit 10 disposed within the fuel reservoir are of a size such that the cross-sectional area of their openings combined will equal substantially the cross-sectional area'of the adjusted opening 16 in the tube 15.

As illustrated in Fig. 3 the fuel chamber of the carbureter communicates through the nozzle 16 with the atomizing chamber 17'. This atomizing chamber communicates with the chamber 18 formed by the elbow 19 through the restricted port 20. The chamber 18 and port 20 constitute the primary intake of the carbureter which is connected with the conduit 7 above referred to.- The elbow 19 carries a stationary rod 21 upon which is slidably mounted a valve 22 seated by means of a spring 23 against pressure within the conduit 7 The chamber 18 communicates with the fuel chamber 9 above the level of the fuel contained therein through the conduit 24. An air intake port is provided at 25 controlled by the valve 26 normally seating against atmospheric pressure for providing communication between the fuel chamber 9 and the atmosphere when acertain predetermined reduction of pressure is produced within the fuel chamber.

As a vacuum or reduction of pressure is produced within the atomizing chamber 17 the pressure within the chamber 18 is also reduced, but on account of the restricted port 20 the pressure within the chamber 18 coming air before it reaches the carbureter. is always slightly greater than the pressure within the atomizing chamber 17 Since the fuel chamber 9 communicates with the chamber 18 the pressure within the fuel 'chamber will be substantially that of the chamber 18 which, as has been pointed out, is greaterthan the pressure within the atomizing chamber. This difference in pressure is necessary in order to feed the fuel through the nozzle 16. The reduction of pressure produced within the chamber 18 is substantially constant due to the restricting valve 22, but in order to positively prevent too great a reduction of pressure in the fuel chamber 'the automatic valve 26 is provided to admit air into the fuel chamberwhen the chamber is subjected to a pressure'less than a predetermined amount.

As the level of the fuel in-the fuel chamber is lowered the float valve 11 opens and permits communication between the fuel chamber and the conduit 10. As soon as such communication is provided the pressure within the conduit is lowered and fuel caused to flow upwardly'from the supply reservoir into the conduit. If the reduction of pressure'in the fuel chamber is sufiicient to raise the fuel only a few inches, let us say two inches, the elevated fuel of course does not reach the carbureter but stands in the conduit two inches above the level of the fuel in the reservoir. Since, however, the upper one of the air intake apertures 14 communicates .with the outside atmosphere a bubble of air is taken in throu h thisaperture under the column of e evated fuel. The intermingling of this air bubble. with the fuel serves to reduce the specific gravity of the fuel in the conduit and allows the fuel to be elevated with but a slight reduction of pressure up to the fuel chamber of the carbureter. As the level of the fuel in the reservoir is lowered it is, of course, necessary to elevate the fuel a greater distance which necessitates the reducing of the specific gravity of the fuel in the conduit to a greater extent than is necessary when the supply reservoir is full. When, therefore, the fuel level is lowered more of the apertures 14 are uncovered, each permitting the ifntake of air into the column of elevated uel. apertures 14' are arranged so that no matter at what height the fuel in the supply reservoir stands there will be at all times one air intake opening which is positioned between the level of the fuel in the reservoir and the level'of theele'vated fuel in the conduit so that a bubble of air is formed underneath the column;

Some difliculty has been encountered in the past in using the so-called vacuum system in high altitudes for the reason that the fuel in the supply-reservoiris not subjected to enough pressure to elevate it to It is to be noted that the air; intake the carbureter. Difficulty has also been encountered in this system when climbing hills, since the carbureter is thus on account of the incline positioned a greater distance above the supply reservoir. By the system of my invention these difficulties are overcome and the fuel can be elevated with but a slight reduction of pressure to ac'onsiderable height.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination of an internal combustion engine, a carbureter connected with the intake manifold thereof and having its fuel chamber communicating with the intake manifold, whereby upon operation of the engine the fuel chamber is subjected to pressure below that of atmospheric pressure, a fuel supply reservoir located below the fuel chamber of the carburetor and having the fuel contained therein subjected to atmospheric pressure, and a fuel conduit comcontained therein, that portion of the con municating with the interior of the fuel chamber and extending downwardly through the top of the supply reservoir into the fuel contained therein, that portion of the conduit lying between the top of the reservoir and the fuel contained therein being providedwith an air intake opening.

2. The combination of an internal combustion engine, a carbureter connected with the intake manifold thereof and having its fuel chamber communicating with the intake manifold, whereby upon operation of the engine the fuel chamber is subjected to pressure below that of atmospheric pressure, a fuel supply reservoir located below the fuel chamber of the carbureter and having the fuel contained therein subjected to atmospheric pressure, a fuel conduit communicating with the interior of the fuel cham-- her and extending downwardly through the top of the supply reservoir into the fuel contained therein, that portion of the conduit lying between the top of the reservoir and thefuel contained therein being provided with an air intake opening and means for regulating the air intake opening.

3. The combination -of an internal combustion engine, a carbureter connected with the intake manifold thereof and having its fuel chamber communicating with the intake manifold, whereby upon operation of the engine the fuel chamber is subjected to pressure below that of atmospheric pressure,a fuel supply reservoir located below the fuel chamber of the carbureter and hav-' ing the fuel contained therein subjected to atmospheric pressure, a fuel conduit cornmunicating with the interior of the fuel chamber and extending downwardly through the top of the supply reservoir into the fuel duit lying between the top of the reservoir and the fuel contained therein being provided with an air intake opening and means operable from the outside of the supply reservoir for regulating the air intake openmg.

4. An automatic feed system for carbureters wherein a fuel supply reservoir is located below the carbureter and in which a reduction of pressure is employed to elevate the fuel from the reservoir through a conduit to the carbureter, having a restricted air intake opening located in the conduit within the reservoir above the level of the fuel in the reservoir and below the level of the fuel elevated by the reduction of pressure in the conduit.

5. The combination of a carbureter, a fuel chamber therefor, means for reducing the pressure in the fuel chamber below atmos-' below the fuel chamber and having the fuel 'contained therein subjected to atmospheric pressure, a conduit communicating with the fuel chamber. and extending downwardly through the top of the reservoir into the fuel contained therein, and a plurality of air intake openings placed one above the other in that portion of the conduit disposed within the .supply reservoir.

6. The combination of a carbureter, a fuel chamber therefor, means for reducing the pressure in the fuel chamber below atmospheric pressure, a supply reservoir located below the fuel chamber and having the fuel contained therein subjected to atmospheric pressure, a conduit communicating with the fuel chamber and extending downwardly through the top of the reservoir into the fuel contained therein, a plurality of air intake openings placed one above the other in that portion of the conduit disposed within the supply reservoir, means connecting all of the apertures with the atmosphere through a single opening, and means for regulating the passage of air through the single opening.

7. In a liquid feed system, the combination of a liquid tank of considerable depth,

a liquid reservoir above the tank, a communication between the tank and the Ieservoir extending to and adapted to draw liquid from said tank throughout a wide range of variation of level of the liquid therein, means to apply suction to the upper part of the reservoir, and means to restrictedly admit atmosphere to said communication at vertically spaced points at least one of which is above the normal liquid level in the tank and others of which are at substantially different depths below said level.

8. In combination with a carbureter, a lowlevel liquid fuel tank, a liquid fuel reservoir above the carbureter and in communication therewith to supply it with fuel, a communication between the tank and reserdownwardly through the top of the reser- -voir, means for restrictedly admitting atchamber therefor, means for reducing the pressure in the fuel chamber below atmospheric pressure, a supply reservoir located below the fuel chamber and having the fuel contained therein subjected to atmospheric pressure, a conduit communicating with the fuel chamber and extending voir into the fuel contained therein, a plurality of vertically spaced openings in said conduit, said openings being uncovered successively as the level of the fuel in said tank drops, a tube around said conduit having a closedupper end and an open bottom end,

the closed end of said tube lying slightly above the level of the fuel insaid reservoir and above the uppermost opening in said conduit, an opening in said tube to admit atmosphere therein from the interior of said reservoir to the openings in said conduit and means operable from the, outside of said reservoir for regulating the size of said opening.

10. The combination of a carbureter, a fuel chamber therefor, means for reducing the pressure in the fuel chamber below atmospheric pressure, a supply reservoir located below the fuel chamber and having the fuel contained therein subjected to atmospheric pressure, a conduit communicating with the fuel chamber and extending downwardly through the top of the reservoir into the fuel contained therein, a plurality of openings in said conduit, said openings being uncovered successively as the level of the fuel in said tank drops, a tube around said conduit having a closed upper end and an open bottom end, the closed end of said tube lying slightly above the level of the fuel in said reservolr and-above the uppermost from the outside of said reservoir for reguopening in said conduit, an opening in said tube to admit atmosphere therein to the openings in said conduit, and means operable from the outside of said reservoir for regulating the size of said opening.

11. The combination of a carbureter, a fuel chamber therefor, means for reducing the pressure in the fuel chamber below atconduit having a closed upper endand an open bottom end, the closed end of said tube lying slightly above the level of the fuel in said reservoir and above the uppermost opening in said conduit, an opening in said tube to admit atmosphere therein to the openings in said conduit, and means operable lating the size of said opening.-

12. The combination of a carbureter, a fuel chamber therefor, means for reducing the pressure in the fuel chamber below atmospheric pressure, a supply reservoir ,lo-

cated below the fuel chamber and having the fuel contained therein subjected to ,at mospherio pressure, a' conduit communicating with the fuel chamber and extending downwardly through the top of the reservoir into openings in said conduit, a tube around saidconduit having aclosed upper end and an i most opening in said conduit, an opening Y in said tube to admit atmosphere therein to the openings in said conduit, and means operable for regulating the size of said, open: mg.

In witness whereof, I' hereunto subscribe my name this 30th day of March, A. D. 1916.

CLIFFORD'C. BRADBURY. Witnesses:

H. A. NEIBURGER, MARY A. (300K.

the fuel contained therein, a plurality of 

